Implicit vs. explicit SSL: what's the diff.?

I am confused about the SSL modes. Whis one between 'implicit' and 'explicit' is more secure? What does each mean? I noticed that when in 'implicit' mode, the little lock on the connection is yellow and that, for 'explicit' mode, it is light blue. Does that mean that 'explicit' is less secure than 'implicit'?

Thanks for the quick reply, LM. The links you offered didn't tell me whether one is more secure than the other. From what I read, I am guessing that implicit is as secure as explicit, but I am not sure. I know this may not be a direct SmartFTP related question, but if you could provide more links that deal with the matter or a quick explanation, it would be much appreciated.